<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>圆角CSS</title>
    <style>
        .container{
            width: 300px;
            margin: 100px auto;
        }

        .one{
            height: 100px;
            width: 150px;
            border: 1px solid blue;
            border-top-left-radius: 40px 20px;
            border-bottom-right-radius: 40px 20px;
            margin-bottom: 40px;
        }

        .two{
            height: 50px;
            width: 150px;
            border: 2px solid black;
            border-radius: 25px;
            margin-bottom: 40px;
            background-color: aquamarine;
        }

        .three{
            height: 60px;
            width: 60px;
            background-color: aqua;
            border: 2px solid black;
            border-radius: 30px;
            margin-bottom: 40px;
        }
    </style>
</head>
<body>
    <div class="container">
        <div class="one"></div>
        <div class="two"></div>
        <div class="three"></div>
    </div>
</body>
</html>